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ES Windows Home Additions & ADU: The San Jose Owner’s Guide
If you’re planning a home addition or ADU in San Jose with ES Windows products, you need a contractor who understands how these window systems integrate with new framing, shear walls, and Title 24 energy requirements. Typical San Jose home additions using ES Windows run $53,100 – $153,400 depending on square footage, roofline complexity, and how many window and door openings you’re adding. Trevor Nash and our Penhallow Remodeling San Jose team install and finish ES Windows on every addition and ADU we build, and we match the right window series to your wall assembly before the first stud goes up.
Most homeowners don’t discover they have an ES Windows compatibility issue until the rough opening is already framed. The window flange doesn’t sit right. The flashing detail fights the stucco profile. Or the inspector flags the header because somebody guessed at the load path. We fix those problems before they become change orders, because we write the window schedule into the plan from day one.
Which ES Windows Models This Applies To
ES Windows manufactures several residential lines that appear regularly in San Jose additions and ADUs. The two you’ll most likely encounter are their aluminum thermally-broken series and their vinyl replacement line. They are not interchangeable in the framing phase, and that’s where a lot of remodelers get it wrong.
For new construction work like an ADU or room addition, the thermally-broken aluminum frames are the better match. They take a nailing flange designed for new openings, and they spec cleanly into a 2×6 wall with the right flashing sequence. For retrofit situations where you’re keeping an existing wall and replacing glass, the vinyl line with a block-frame or pocket-mount installation is the more realistic route.
The critical compatibility check is the frame depth. ES Windows aluminum series often run a 3-1/4″ or 4-1/2″ jamb depth, and your rough opening, interior trim detail, and sill slope all change depending on which one you use. Before we order anything, we measure the existing opening with a laser and verify the model number off the corner tag if you have it. If the tag is missing, we pull a sash and check the spacer bar and glazing bead profile. Aftermarket glass can fit, but for anything tied to the addition’s structural integrity or the city’s Title 24 inspection, we specify OEM ES Windows frames and glazing. The thermal break is part of your energy compliance, and a knockoff that skips that detail costs you down the road.
Styles & brands we work with
Signs Your ES Windows Home Addition or ADU Needs Attention
- Condensation between the panes. The desiccant in the spacer bar has failed and the insulated glass unit has lost its seal. In San Jose’s dry summers this may look minor, but once moisture fogs the glass you’re looking at a replacement IGU, not a cleaning fix.
- Water staining on the interior drywall below a window. The flashing or sill pan wasn’t installed correctly when the addition was framed. We see this a lot in Almaden Valley and Willow Glen additions where stucco meets a flanged window with no backer rod or sealant bead.
- Operable sashes that bind or drag. The frame has moved or the foundation settled slightly, throwing the reveal out of square. In San Jose’s clay soils, seasonal movement is common, and a window that binds in January may slide fine in August.
- Drafts you can feel at the head or jamb on cold mornings. The jamb gasketing has compressed, or an aftermarket glazing bead doesn’t match the original extrusion profile. Air leakage at the frame also fails blower-door testing if you go for ADU energy certification.
- Fogging, haze, or a milky film that won’t wipe off. This is a failing low-E coating breaking down inside the IGU. Once the coating starts to oxidize, the window has to be reglazed. There isn’t a film or polish that restores it.
See the difference
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After
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After
Before
AfterReplacement Cost & What’s Included
If your San Jose home addition or ADU already uses ES Windows and a unit needs replacing, installed glass-and-frame replacement runs roughly $944 – $2,950 per opening depending on size, glass package, and whether it’s an operable sash or a fixed picture window. A full window replacement within an addition or ADU project typically falls in the $5,310 – $17,700 range when you’re doing multiple units at once.
For new additions and ADUs, you’re pricing the whole scope, not individual windows. The $53,100 – $153,400 range reflects the shell, framing, electrical, drywall, insulation, HVAC tie-in, and the window package together. A single-bedroom ADU with three or four ES Windows openings typically lands on the lower end once you factor in site conditions. A two-story addition with custom glazing, a full bathroom, and a kitchenette pushes toward the upper end. We give you a written line-item price before work begins, and the window schedule is listed on that document by model, size, and glass spec. No verbal ranges. No surprise “upgrades” at rough-in.
Every window we install carries our written 365-Day Done Right Promise. If a unit fogs, leaks, or fails to operate properly within the guarantee period, we come back and fix it at no charge. If we can’t repair it, we replace it.
DIY or Call Us?
There are a few things you can safely check before you call. Look for the corner tag on the inside of the sash or the head of the frame. That tag has the model series and the IGU thickness, which tells us whether it’s original to the addition or an aftermarket swap. Check the exterior caulk bead at the top corners where the horizontal and vertical trim meet. If it’s cracked or pulling away, that’s a leak path you can identify on your own.
What you should not do is pull a sash, remove a glazing bead, or try to reset a window on your own. A tilted or misloaded insulated glass unit is razor-sharp at the edge and surprisingly heavy, and a window that’s part of a load-bearing wall needs to be handled by someone who understands header loads and shear transfer. If the opening moves, you’re not fixing it with shims. Trevor’s rule from years of framing in Willow Glen and across the South Bay: “Give me the real problem and I’ll give you the real number.” If you’re not sure what you’re looking at, call us at (669) 274-2362 and describe the symptom. We’ll tell you over the phone whether it’s worth a service visit.
FAQs
Expect 20 – 30 years from the frames and 15 – 25 years from the insulated glass, though San Jose’s intense summer UV shortens the lifespan of low-E coatings on south and west exposures. Windows on the south side of an addition in Evergreen or Silver Creek often lose their seal a few years earlier than the same window on a shaded north wall.
Sometimes. If the problem is worn gasketing, a bent operator, or a failed seal on an otherwise square frame, a reglaze or hardware swap fixes it for $295 – $825 depending on the part. If the frame is twisted, the corner keys are cracked, or the aluminum is heavily pitted from coastal air, replacement is the more honest answer, and we’ll tell you which one applies before you spend anything.
A single retrofit window replacement usually takes half a day. A full addition or ADU with new ES Windows typically runs 3 to 6 months from first inspection to final walkthrough. The window installation itself happens in a coordinated sequence with framing, waterproofing, and drywall, so it’s scheduled as part of the whole build, not as a standalone event.
We keep common ES Windows hardware, gasketing, and glazing bead profiles on the truck for San Jose jobs, and we source full frames and IGUs directly through our ES Windows supply channel, not through a middleman’s markup. That means our written price reflects what we actually pay for the part, plus straightforward labor. If the part you need is backordered, we tell you the real lead time before you commit.
If you’re planning a home addition or ADU in San Jose and want the window schedule done right the first time, call (669) 274-2362. We’ll give you a written price, a real arrival window, and a 365-day guarantee on the work. You won’t get a voicemail, and you won’t get pressure. You’ll get an answer.
Written by Trevor Nash, Owner, Penhallow Remodeling San Jose at Penhallow Remodeling San Jose, serving San Jose and nearby areas.
